EZ-EFI 388ci Muscle Mouse

F.A.S.T. Learner

Last month we covered a stout 388ci small-block combination that Vrbancic Brothers Racing in Ontario, California, assembled with pump gas power in mind. Details include, 9.7:1 compression, a set of RHS 200cc aluminum heads, an RHS single-plane intake manifold, and a fairly aggressive hydraulic roller camshaft (242/248-degrees of duration at 0.050). While we had our default goal of 500hp on pump fuel in mind, we'd be happy with anything over 450, and if it's like any of the other stroker small-blocks we covered this year, our 388 should be right in there. Unlike the carbureted strokers we dyno'd in the past year, we wanted to try something different on this combination, namely F.A.S.T.'s EZ-EFI system. We've heard great things about the self-learning technology and we were anxious to try it out in a controlled environment like Vrbancic's engine dyno.

Hooking up the system is almost as simple as installing a carburetor, with minimal connections required for operation, a handheld interface module, and with help from the Setup Wizard, it makes installing EFI on your engine easier than it's ever been. This setup is designed for engines up to 650 horsepower and the system guides the user through startup and operation; it literally tunes as you drive.

If you have a 4150-style intake manifold and you're looking to improve gas mileage or to improve your startup reliability, this is a great system. The setup comes with a high-flow throttle-body with injectors and rails installed, an ECU that features internal diagnostics, a palm-held tuning module, a fuel pressure regulator and in-line fuel pump and filter; the pre-terminated wiring harness also makes install a breeze.

EZ-EFI Tips

Make sure to position the ECU away from any electronics, such as spark plug wires, the coil, or anything that would produce noise that could confuse the system.

The system hooks up via AN-6 fuel lines so a variety of hoses and fittings this size is a must for install. F.A.S.T.'s Master Kit (PN 30227-KIT) supplies all the hoses and fittings needed in a complete kit.

The wide band O2 sensor should be installed within 1 foot downstream of the header or manifold collector.

According to F.A.S.T., the A/F targeting in the ECU is pre-set and self taught. For those that know what they are doing and are interested in adjusting the targets directly, the hand held advanced section allows for those fine adjustments. It's important to note that this is not necessary and strictly optional.

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1. If you’re looking for an added visual touch, then check out the custom valve covers by Eddie Motorsports, Inc.; the tall smooth valve covers with a colored finish priced out at $110 for the set. The additional engraving charges will vary with the art work supplied, but it generally starts at $25 for the pair.

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2. Before bolting up the 388 to the engine dyno, Bob Vrbancic made sure to install the TCI Auto Rattler harmonic balancer. These are laser-etched with timing marks and an internal system that absorbs harsh harmonics.

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3. PerTronix supplied the ignition on this combo, including their Flame Thrower coil and billet distributor with the Ignitor II module.

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4. Vrbancic changed the mechanical advance to ensure that it had 36-degrees of total timing.

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5. The F.A.S.T. throttle-body comes with the injectors and rails in place. The fuel injectors are large units that can support up to 650 horsepower.

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6. The EZ-EFI system uses the engine’s temperature as a reference to begin learning; the system doesn’t start hunting for its target A/F ratio until after the engine temperature reaches 180-degrees.

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7. This image shows the throttle position sensor (bottom sensor) and the air temperature sensor. Each of these connects to the harness with clearly labeled, pre-terminated wires.

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8. The manifold air pressure sensor is another critical connection; the MAP sensor’s function is to communicate data to the ECU that represents the pressure inside the manifold and the mass of air and the flow rate. With this data, the ECU is able to determine how much fuel is needed for ideal combustion.

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9. The idle air control actuator is a valve that basically controls the idle speed on an EFI setup. The ECU communicates to this sensor how much air to bypass into the engine, allowing it to idle at the user’s programmed target speed.

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10. The wideband O2 sensor is the gatekeeper of your engine’s tune up. This sensor monitors the A/F ratio in the exhaust and the ECU uses the data collected to correct and fine-tune the amount of fuel according to the user’s selected targets.

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11. We opted to go with the F.A.S.T. fuel pressure regulator on this build as well, which is setup to keep the high fuel pressure in check throughout the rpm range.

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12. Before firing up the 388ci, Vrbancic poured in six quarts of COMP Cams 10W30 Engine Oil into the motor. The oil, which is designed with muscle car engine specifically in mind, is a synthetic blend. We’ve been using this stuff on all of our performance engines lately and it’s nice to have something with a name you can trust lubricating your engine.

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13. Tuning using the setup wizard is a breeze; it starts with a simple selection of the cubic inches. The ECU is programmed to know a ballpark of how much fuel is required according to the cubic inches and it fine tunes itself from here.

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14. One of the other screens asks for a desired idle speed. This simply communicates with the IAC to provide your desired idle.

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15. The fuel pressure must also be input into the setup wizard.

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16. In order for the ECU to see wide open throttle, you must open up the throttle body fully to give the TPS a reference.

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17. This screen shows what the setup wizard looks like during warm up. You can see on the bottom portion of the screen the computer will correct the A/F ratio until the bars are happily bouncing in that target zone. The system will continue to warm up and learn, until the progress bar is in the target area.

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18. The Live Data mode on the interface shows the correction factor in terms of percentage. In our case it was correcting by -12 percent in order to reach our desired target.

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19. For experienced tuners, EZ-EFI does allow for fine adjustments in the advanced menu.

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20. For air filtration, Airaid supplied a Race Element filter that only has the screen and no gauze. This high-flow filter will keep larger debris out of your engine, but will flow a ton compared to a full element piece.

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21. While we didn’t get 500 horsepower out of our 388ci, we did get to learn all about how the F.A.S.T. EZ-EFI system works. Once the ECU learned our parameters, the engine generated 474.1 horsepower and 461.2 lb-ft of torque. For the final pull of the day, we tried adding a 1-inch carb spacer and increased the performance to 481.4 horsepower at 6,000 rpm and 467.4 lb-ft at 5,000 rpm. Being that this is a self-learning system, it will improve even more each time you drive it. We used it on an engine dyno to view how it functions, but if you’re going to run this system we recommend setting it up in the car so the ECU can see all the factors, especially since engines typically run differently in the car than they do on the dyno. There you have it; a simple bolt-on that brings any street machine to modern day standards. CHP